From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5BE11C2D0E0 for ; Thu, 3 Sep 2020 20:35:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39FBE20639 for ; Thu, 3 Sep 2020 20:35:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="mF0WB4Q1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728975AbgICUfe (ORCPT ); Thu, 3 Sep 2020 16:35:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35526 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729513AbgICUcr (ORCPT ); Thu, 3 Sep 2020 16:32:47 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B243DC0619E8 for ; Thu, 3 Sep 2020 13:31:28 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id r1so4096570ybg.4 for ; Thu, 03 Sep 2020 13:31:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=uaTfkB4ak1aJZWY50HSjxViiXLY/kut+uNnKrezpcK8=; b=mF0WB4Q1ilKN/2ZqpXw5x4/HmJUMwCWGi2P+cTr/YpR+8mKfhxtAQ98O8PqGynIC8O SEOr8J0gsFlwzelGzRV17yurypMIXiNJ55R0Ym5qIIwq+cQiNZ/t4akGHBiu14GZxifB mGzV4o2ZdqIe4cXD+oWt+lNNks1pqY9XmZ8qYRr8AF+yz2wMbwhUJW9NadF6++sNk6qg k6gt9RssqRm8Ro+SLyHZewy2mRecQrib+ApgUWgcAWDaDTixRz6n/GojNuc8DZQ0zJwb gqJSHHf8ovZr9XJCJdpQFTPz3QtwXORXLXWqFrqr3VgOKkRiidqDj1RYJuMC+BGncMrH crQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=uaTfkB4ak1aJZWY50HSjxViiXLY/kut+uNnKrezpcK8=; b=K14WA/72gBsuY7RPajt96bYXkTyBpfC69l9Q7ZNlGw+FzqYuHuwLw9hkjFchdtrttO AGWQg5hrBFSmh/XX6wpaCpLPs39JO2np9GBeKAmI2vayYJhVsBzBUPW1xwN/flAmNha0 mwDHNC1TG1R3fYJK80fVPlD5V3Q4dEOStzIJ1gijx4GW3gL/Zqv41cyh0Z62sNloUTRu OctE/R6mPf/Bffb/qaI+VcB0OlMqcyheam2ZJGWntv527gpPEY2s0FGDC/Kxgt1k6P7Z CydsoNTqI4mIVRHnuXyF3234/vFqXvjr8DVCscvRZ75c9E14SUm354bx+uuTBRsdkpF3 FWHQ== X-Gm-Message-State: AOAM530GgUyOUu69knz895vixiFLRCJff1bUI+xVT8g+8KMkqleLQGdK 5Ab9pU3WoasUXq67wyUHsGn3ZjD54p50tqtsThs= X-Google-Smtp-Source: ABdhPJxkMmB21+S7VY0Jt9zVeucemxfhi5zBK41/ZcXFOz1RBFo/uHKHBl3+bP1fnXBaBCAh+O4Eoo9Dz40YO9G7Tzc= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:f693:9fff:fef4:1b6d]) (user=samitolvanen job=sendgmr) by 2002:a25:cdca:: with SMTP id d193mr5380428ybf.402.1599165087915; Thu, 03 Sep 2020 13:31:27 -0700 (PDT) Date: Thu, 3 Sep 2020 13:30:41 -0700 In-Reply-To: <20200903203053.3411268-1-samitolvanen@google.com> Message-Id: <20200903203053.3411268-17-samitolvanen@google.com> Mime-Version: 1.0 References: <20200624203200.78870-1-samitolvanen@google.com> <20200903203053.3411268-1-samitolvanen@google.com> X-Mailer: git-send-email 2.28.0.526.ge36021eeef-goog Subject: [PATCH v2 16/28] init: lto: fix PREL32 relocations From: Sami Tolvanen To: Masahiro Yamada , Will Deacon Cc: Peter Zijlstra , Steven Rostedt , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, x86@kernel.org, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org With LTO, the compiler can rename static functions to avoid global naming collisions. As initcall functions are typically static, renaming can break references to them in inline assembly. This change adds a global stub with a stable name for each initcall to fix the issue when PREL32 relocations are used. Signed-off-by: Sami Tolvanen --- include/linux/init.h | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/include/linux/init.h b/include/linux/init.h index af638cd6dd52..cea63f7e7705 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -209,26 +209,49 @@ extern bool initcall_debug; */ #define __initcall_section(__sec, __iid) \ #__sec ".init.." #__iid + +/* + * With LTO, the compiler can rename static functions to avoid + * global naming collisions. We use a global stub function for + * initcalls to create a stable symbol name whose address can be + * taken in inline assembly when PREL32 relocations are used. + */ +#define __initcall_stub(fn, __iid, id) \ + __initcall_name(initstub, __iid, id) + +#define __define_initcall_stub(__stub, fn) \ + int __init __stub(void); \ + int __init __stub(void) \ + { \ + return fn(); \ + } \ + __ADDRESSABLE(__stub) #else #define __initcall_section(__sec, __iid) \ #__sec ".init" + +#define __initcall_stub(fn, __iid, id) fn + +#define __define_initcall_stub(__stub, fn) \ + __ADDRESSABLE(fn) #endif #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS -#define ____define_initcall(fn, __name, __sec) \ - __ADDRESSABLE(fn) \ +#define ____define_initcall(fn, __stub, __name, __sec) \ + __define_initcall_stub(__stub, fn) \ asm(".section \"" __sec "\", \"a\" \n" \ __stringify(__name) ": \n" \ - ".long " #fn " - . \n" \ + ".long " __stringify(__stub) " - . \n" \ ".previous \n"); #else -#define ____define_initcall(fn, __name, __sec) \ +#define ____define_initcall(fn, __unused, __name, __sec) \ static initcall_t __name __used \ __attribute__((__section__(__sec))) = fn; #endif #define __unique_initcall(fn, id, __sec, __iid) \ ____define_initcall(fn, \ + __initcall_stub(fn, __iid, id), \ __initcall_name(initcall, __iid, id), \ __initcall_section(__sec, __iid)) -- 2.28.0.402.g5ffc5be6b7-goog